Electromagnetic body



Patented Aug. 20, 1929.

UNITED STATES PATENT OFFICE.

RICHARD SWINNE, OF STEGLITZ, BERLIN, GERMANY, ASSIGNOR T SIEMENS &

HALSKE AKTIENGESELLSCHAFT, 0F SIEMENSSTADT, NEAR BERLIN, GERMANY, A

COMPANY OF GERMANY.

ELECTROMAGNETIC BODY.

No Drawing. Application filed April 15, 1927, serial No. 184,188, and in Germany May 17, 1926.

This invention relates to electromagneticbodies, particularly those which are made from finely divided magnetic material, such as ferro-magnetic material, and a mechanical,

electrical, or magnetic insulatin separating means in solid or originally fiui form separating the finely divided particles. The body can be used as a. core for electromagnetic relays, measuring instruments, transformers, electric or magnetic power generating machines for direct current or alternating current operation up to the highest frequency, repeating coils, loading coils and for continuous loading for telephone urposes.

The invention, which is due to t e observation that monocrystalline ferro-magnetic materials exhibit practically negligible hysteresis losses, consists in using amagnetic material, such as a ferro-inagnetic material,

in monocrystalline form to form an electromagnetic body instead of the polycrystalline form of magnetic material used quitegenerally heretofore. The monocrystals may be of any desired size or shape to render them best suitable under the conditions for which they are to be used. For example, the monocrystalline magnetic material in the form of bars or rings consisting of a single crystal may be of advantage for use as cores for repeating and loading coils, but it may be desirable also to reduce the crystal size by'well known methods and produce the ferro-magnetic material in the form of a monocrystalline powder which may be used for making dust magnetic cores withthe addition of a mechanically, electrically, or magnetically insulating material for separatin the magnetic particles so as to reduce the e dy current losses and raise the magnetic stability. For

40 the manufacture of such. dust cores any of the well-known methods applying high,

mean, or zero pressure may be employed, but

those using low or zero pressure may be used to advanta e. When using high pressure,

4 care must e taken that the pressure acts omnilaterally, since by unilateral pressure or impact the monocrystalline powder may pass into the polycrystalline form.

The same processes may be employed in the manufacture of bars or bodies of other shapes. Under certain conditions, however,

it is not a disadvantage if during the manufacture of the monocrystalline bodies or afterwards some conversion into the polycrystallineform takes place.

A suitable material for use in the electromagnetic body of the invention is a ferromagnetic material, such asiron, but other pure metals, such as nickel and cobalt and also binary alloys of these metals may be used. For example, the magnetic material may comprise iron and in addition silicon, aluminum or similar material for increasing the permeability, and also suitable ironnickel alloys may be employed. Moreover, ternary or even higher alloys of any of the above-mentioned materials with other metals giving good solid structures, for example, copper, chromium or the like or Heuslers' alloys may be employed.

For the purpose of making monocrystalline bodies several methods are already wellknown, such as the fusing or freezing process and the recrystallization method. An article b P. W. Bridgman in the proceedings of the erican Academy of Arts and Sciences, vol. 60, pp. 305-385 (October, 1925) describes a method of making single crystals by freezing. An article by Honda and Kaya, in the Science Reports of the Tohoku Imperial University, vol. 15, pp. 721-7 53 (1926) describes a method of makingsingle crystals by recrystallization. In order to obtain monocrystalline bodies of magnetic material in powder form, however, more recently developed methods are needed which will be described below in accordance with this invention. If as the starting materials metal compounds are chosen which can be volatilized under suitable temperature and pressure conditions, the speed of decomposition is so chosen that the separation of the metal takes place in the desired monocrystalline form. This would be the case, for instance, with the carbon ls of nickel or iron. An article by A. E. an Arkel in the Chemische Weekblad, vol. 24, pp. 90-96 (1927) [abstracted in Chemical Abstracts, vol. 21, 1731 (1927)] and an article by de Boer and Fast in .Zeitschrift f. anorganishche allgemeine Chemie, vol. 153, pp. 1 8 (1926) [abstracted in Chemical Abstracts, vol. 20, 2627 (1926); describe methods of making single or sta s by condensation of, a metal vapor or 0 a vapor compound. If an electrolytic method is. employed the separation into monocrystalline form is performed by suitably choosing the factors influencing the separation, such as current density, concentration, temperature,

state of combination (in simple or complex.

ions) and the surface characteristics of the electrodes. The making of single crystals of tin by such an electrolytic method is described in a book Chemische Kr stallographie by Paul Groth, Teil 15, eipzig, Wilhelm Englemann, 19061919, pp. 14-15, and in an article by W. H. Miller in the Philosophical Magazine, vol. 22, series 3, pp. 263265, April 1843.

lVhat is claimed is:

1. An electromagnetic body comprising a magnetic material in the form of a single crystal.

2. An electromagnetic body having low hysteresis and edd current losses comprising a mass of fine y divided particles of a magnetic material in monocrystalline form, and an insulating material separating the particles.

3. An electromagnetic body in accordance with claim 2 and in which said finely divided particles of monocrystalline magnetic material include iron.

4. An electromagnetic body in accordance with claim 2 and in which said finely divided particles of monocrystalline magnetic material comprise a condensate of a metal carbonyl.

5. An electromagnetic body in accordance with claim 2 and in which said monocrystalline particles of said magnetic material comprise a condensate of iron carbonyl.

In witness whereof, I hereunto subscribe my name this 23rd day of March A. D., 1927 RICHARD SWINNE. 

